Resettable fire damper

ABSTRACT

The folding blade type fire damper is provided with a thermally actuated resettable release link and retraction means cooperating with the link to reset the blades in their retracted condition upon actuation from outside the duct in which the damper is mounted.

3,79 ,249 [451 Mar. 12,1974

United States Patent McCabe X U 5 7 O 2 6 2 1 2,148,530 2/1939 Burke........................ 3,665,996 3,273,632 3,687,185

1 RESETTABLE FIRE DAMPER /1972 Roberts..... 9/1966 McCabe....

[76] Inventor: Francis J. McCabe, Rt. 413, R0.

[22] Filed:

Primary Examine -Mervin Stein Assistant Examiner-Philip C. Kannan Related U.S. Application Data [63] Continuation-impart of Ser. Nos. 178,111, Sept. 7,

1971, Pat. No. 3,725,972, and Ser. No. 284,221, Aug. 28, 1972.

ABSTRACT 160/1, [60/35, [60/84 Int.

E051 /20 The folding blade type fire damper is provided with a [58] Field of 160/1, 5, 6, 84, 35, 36; thermally actuated resettable release link and retrac- 126/2875, 285; 137/457, 79; 98/85, 86; tion means cooperating with the link to reset the blades in their retracted condition upon actuation from outside the duct in which the damper is v mounted.

2 Claims, 5 Drawing Figures PATENTEUIAR 12 I974 SHEET 2 OF 2 RESETTABLE FIRE DAMPER BACKGROUND OF THE INVENTION This invention relates to fire dampers for use in air ducts, and more particularly, to fire damper operators which are designed to hold the damper in the open position under normal usage, and release and automatically close the damper under fire conditions.

In the prior art, folding blade fire dampers such as those shown in my US. Pat. Nos. 3,273,632, and 3,401,734, were retained in a folded or retracted condition by a wire or chain held by a fusable link. The link was not resettable, but was wasted once it was used.

In my prior copending applications I disclosed a resettable link which can be actuated by a remote electri- SUMMARY OF THE INVENTION My invention provides a resettable means for a fire damper, cooperating with a resettable link upon remote actuation from outside the air ductin which the damper is mounted. In the embodiment principally disclosed in the present application the resettable link is mounted outside the air duct so as to be exposed to heat from fire outside the air duct to thereby actuate the link and release the damper blades. The means for resetting the damper blades comprises a flexible member for raising the blades in the damper to their folded condition from outside the air duct. The flexible member engages the link to retain the blades in their folded condition until the link is actuated to release them.

Accordingly, it is an object of my invention toimprove fire damper systems by providing a means for re-, motely opening and resetting dampers mounted in ducts.

This and other objects of my invention will become apparent from the following description with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation of a remotely resettable folding blade fire damper in accordance with my invention shown partially in section, mounted in its environmental condition with alternate positions shown in phantom lines;

FIG. 2 is a view taken as indicated by the lines and arrows 22 in FIG. 1, foreshortened for the sake of clarity;

FIG. 3 is an enlarged view of a portion of the apparatus shown in FIG. 2, shown partially in section;

FIG. 4 is a view taken as indicated by the lines and arrows 44 in FIG. 3; and

FIG. 5 is a view of a portion of the apparatus shown in FIG. 4, shown in an alternate position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although specific forms of the invention have been selected for illustration in the drawings, and the following description is drawn in'specifi'c terms for the purpose of describing these forms of the invention, this description is not intended to limit the scope of the invention which is defined in the appended claims.

A folding blade fire damper is shown in elevational view in FIG. 1 and designated generally 10. In this type of fire damper a header section, designated generally 12, is provided. The damper is mounted in its environmental condition so that the air ducts shown in phantom lines and designated generally 14 and 16, are connected to the damper or a sleeve at the bottom 18 and at the flanges 20 and 22 of the top header 12.

The damper comprises a plurality of blades shown schematically and designated generally 24. The header retains the blades in the folded condition shown in full lines so that the blades are out of the flow path of the air through the ducts. In this folded or retracted condition the blades are held by a flexible member or cable or wire 26. The wire is connected at one end by passing it through a hole in the damper frame 28 and the header portion 12, and attaching a metallic clip 30 to the end as by crimping. The metallic clip is of such a diameter that it will not pass through the holes. When the flexible member 26 is released, the blades will descend by the force of gravity to their unfolded or fully extended condition shown at A in FIG. 1.

In accordance with the present invention, I have provided a means for resettingthese blades in their folded condition which means can be actuated from outside the duct. The resettable means is manually actuated by pulling on the cord or wire 26 and looping it about a pin in a resettable link. This portion of the invention is more fully understood by reference to FIGS. 2 through 5. FIG. 2 shows an elevation which has been foreshortened for the sake of clarity, of the fire damper shown in FIG. 1 when viewed from the righthand side. Therein it will be noted that the wire 26 passes through a hole 40 in the header 12 and then is wrapped about the lower portion of an angle bracket 42 (shown also in FIG. 1) which is fixedly mounted to the outside of the header by any suitable means, such as spot welding. It will be noted in FIG. 1 that, as the wire 26 passes beneath the angled bracket, it is lodged in a detent 44, the surface of which is preferably smooth and rounded so as to provide a bearing means while the detent itself provides a guide means. The wire 26 then passes through an elongated slot 46 in FIG. 1 across the width of the damper to another angled bracket 48. This angled bracket is suitably affixed to the header l2 and extends perpendicularly therefrom as shown in the drawings. The wire 26 is disposed in another detent as it is passed about the outer end of the bracket 48. The wire is then formed in a loop about the pin 50 of the link designated generally 52 (FIG. 3). From there the wire proceeds back through the detent 54 (FIG. 3) in the bracket 48 and returns to the elongated slot 46 to ultimately have its end fixed by passing it through the bracket 42 and attaching a metallic clip 56 as by crimping. By this means sufficient wire is provided so that when the pin 50 releases the loop in the wire 26, as will be more fully described hereinafter, there is sufficient wire to allow the blades to expand from their folded position to their fully unfolded position as shown at A in FIG. 1. To retract the blades from the unfolded posi tion the wire is grasped and pulled through the hole 40 from outside the duct. A loop is formed in the wire and loop is fed through the elongated slot 46, then as the wire is continually drawn out of the damper the blades move from the position shown at A to the position shown at B" in FIG. 1 and ultimately to the fully retracted condition shown in FIG. 1. In the fully retracted condition the end of the wire is passed about the detent 54 in the bracket 48 and the pin 50. is inserted in the loop in the end of the wire 26, by bending the member 60. V I

The release means which cooperates with the flexible member 26 to both release the blades and retain them in their folded condition, comprises a thermally actuated resettable link. This link has been fully described in my prior pending applications and the disclosure of those applications is incorporated herein by reference. Suffice it to say for present purposes that the link comprises a plurality of metal strips, each electrically insulated from one another. The outer strip 60 is a bimetallic, thermally responsive element which, when duct it will react to fire conditions outside the duct. It

canalso be electrically actuated by means of a circuit comprising the electrical leads designated generally 62 in FIG. 3, and the electrical switch means provided by the contacts designated generally 64 in FIGS. 4 and 5. When the switch is closed as in FIG. 4 and the circuit is actuated, heat is provided directly by electrical current in the element 60 to move it in the direction C until the switch is opened as in FIG. 5. Element 66 is not a bi-metallic element but is spring biased to move also in the direction of C from the position shown in FIG. 4 to a maximum position shown in FIG. 5 so that the circuit automatically breaks by virtue of the fact that the heated element 60 continues to move for a short duration even though the element 66 has stopped its movement.

As stated in a prior application on the link, the bimetallic element could be reversed so that the circuit would have to be constantly providing heat to the bimetallic element to retain it in the position shown in FIG. 4 and then if the circuit was interfered with or broken the heat would be discontinued, allowing the bimetallic element to resume its normal position which would then be that shown in FIG. 5. This alternate type of operation would be useful in a totally electrically controlled system, particularly where it would be desirable to provide some delay in actuating of-the fire mechanism to allow for relief generators to take over in the event'of a power failure. In such a case there would be a slight time delay before the lack of heating to the element 60 caused it to fully open as in FIG. 5 giving some time for the auxiliary electric generators to come on line.

It will be understood that various changes in the details, materials and arrangement of parts which have been herein described and illustrated in order to ex- .plain the nature of this invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the following claims.

It will be further understood that the Abstract of the Disclosure set forth above is intended to provide a non-legal technical statement of the contents of the disclosure in compliance with the Rules of Practice of the United States Patent Office, and is not intended to limit the scope of the invention described and claimed herein.

What is claimed is:

1. In combination with a folding blade damper having blades movable between a folded and unfolded condition, the improvement comprising: a resettable blade retraction means connected to said damper to move the blades from their unfolded condition to their folded condition and retain them in their folded condition upon manual actuation from outside said damper; sa-id resettable blade retraction means comprising a flexible member attached to-said damper and connected to a releasable retaining means; a plurality of brackets attached to the outside of said damper; said flexible member being passed about said brackets to take up the slack in said flexible member and to retain said flexible member in a taut condition while said blades are retained in their fully retracted condition; said releasable retaining means comprising a bimetallic element cantilevered from a support fixed relative to said damper; said element having a pin at the free end thereof for engaging a loop formed in said flexible member and thereby retaining said flexible member in a taut condition as aforesaid.

2. A method of resetting the blades of a folding blade fire damper in their folded condition from outside the damper frame, said damper having a plurality of blades extending between a folded and unfolded condition and being embraced in part by a flexible member which coacts with a releasable retaining means comprising a bimetallic element cantilevered from a support fixed relative to said damper frame, said element having pin extending from the free end thereof for engaging said flexible member, thereby retaining it in a taut condition while said blades are retained in their fully retracted condition; said damper frame having a plurality of flanges extending from the outside thereof, comprising slack and then looping it about said pin. 

1. In combination with a folding blade damper having blades movable between a folded and unfolded condition, the improvement comprising: a resettable blade retraction means connected to said damper to move the blades from their unfolded condition to their folded condition and retain them in their folded condition upon manual actuation from outside said damper; said resettable blade retraction means comprising a flexible member attached to said damper and connected to a releasable retaining means; a plurality of brackets attached to the outside of said damper; said flexible member being passed about said brackets to take up the slack in said flexible member and to retain said flexible member in a taut condition while said blades are retained in their fully retracted condition; said releasable retaining means comprising a bimetallic element cantilevered from a support fixed relative to said damper; said element having a pin at the free end thereof for engaging a loop formed in said flexible member and thereby retaining said flexible memBer in a taut condition as aforesaid.
 2. A method of resetting the blades of a folding blade fire damper in their folded condition from outside the damper frame, said damper having a plurality of blades extending between a folded and unfolded condition and being embraced in part by a flexible member which coacts with a releasable retaining means comprising a bimetallic element cantilevered from a support fixed relative to said damper frame, said element having pin extending from the free end thereof for engaging said flexible member, thereby retaining it in a taut condition while said blades are retained in their fully retracted condition; said damper frame having a plurality of flanges extending from the outside thereof, comprising the steps of: withdrawing a portion of the flexible member through the damper frame to thereby shorten the portion of said member within said frame and simultaneously move the blades from an unfolded to a folded condition; and then manually setting the flexible member so that it maintains the blades in their folded condition, by wrapping it about said flanges to take up the slack and then looping it about said pin. 